An information sharing apparatus comprises extracting unit extracting personal information item from acquired information item which includes personal information item, generating unit generating anonymous information item by deleting personal information item from acquired information item, storing unit storing personal information item and anonymous information item, storing unit storing first access level assigned to group of users who can access only anonymous information item, and to store second access level assigned to group of users who can access both of anonymous information item and personal information item, receiving unit receiving request message for accessing acquired information item, transmitting unit transmitting only anonymous information item when access level predetermined to user is equal to first access level, synthesizing unit synthesizing personal information item with anonymous information item, transmitting unit transmitting regenerated second information item, when access level of user is equal to second access level.